1. Field of the Invention
The present invention relates to a safety device for a photocopying machine especially of the type having a thermal fixing means.
2. Description of the Prior Art
The conventional copying or photocopying machines are generally provided with a safety device of the type in which an expectant time when a copy is to be discharged out of the photocopying machine is measured from the time when the actuation of a copying paper feeding system is started so that when the copy is not discharged out of the photocopying machine even after the expectant time, the alarming signal indicating the possibility of jamming of copying paper in the fixing station is generated so as to stop the operation of the photocopying machine. The safety device of the type described also interrupts the operation of the photocopying machine at the time when the stocked copying paper is exhausted or run out when the timing of feed of copying paper is delayed or when the failure in feeding copying paper occurs due to the slippage of copying paper over feed rollers. Every time when the operation of the photocopying machine is stopped, the heaters in the fixing station are de-energized so that the photocopying operation cannot be resumed immediately after the cause for failure has been checked and removed by an operator because the fixing station is cooled to a temperature below the operating temperature. It generally takes a long time before the temperature in the fixing station rises to the operating temperature.
Furthermore there is a danger for an unskilled operator to restart the photocopying machine without removing the real cause for jamming so that jamming occurs again immediately, thus leading to the serious damages to the photocopying machine.
An object of the present invention is therefore to provide an improved safety device for a photocopying machine which functions depending upon the causes for failures in feeding and discharging photocopying paper so that the safeguarded and efficient operation of the photocopying machine may be ensured.